CVE-2022-49340

Medium

In the Linux kernel, the following vulnerability has been resolved: ip_gre: test csum_start instead of transport header GRE with TUNNEL_CSUM will apply local checksum offload on CHECKSUM_PARTIAL packets. ipgre_xmit must validate csum_start after an optional skb_pull, else lco_csum may trigger an overflow. The original check was if (csum && skb_checksum_start(skb) < skb->data) return -EINVAL; This had false positives when skb_checksum_start is undefined: when ip_summed is not CHECKSUM_PARTIAL. A discussed refinement was straightforward if (csum && skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_start(skb) < skb->data) return -EINVAL; But was eventually revised more thoroughly: - restrict the check to the only branch where needed, in an uncommon GRE path that uses header_ops and calls skb_pull. - test skb_transport_header, which is set along with csum_start in skb_partial_csum_set in the normal header_ops datapath. Turns out skbs can arrive in this branch without the transport header set, e.g., through BPF redirection. Revise the check back to check csum_start directly, and only if CHECKSUM_PARTIAL. Do leave the check in the updated location. Check field regardless of whether TUNNEL_CSUM is configured.

Package Linux Kernel
Published 2025-02-26
Last modified 2025-10-21
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected versions

Linux kernel versions 4.19.207, 5.4.148, 5.10.68, 5.14.7, 5.15 and later are affected. Fixed in 4.19.247, 5.4.198, 5.10.122, 5.15.47, 5.17.15, 5.18.4, 5.19 and their respective stable series.

Affected from
≥ 4.19.207 ≥ 5.4.148 ≥ 5.10.68 ≥ 5.14.7 ≥ 5.15
Fixed in
✓ 4.19.247 4.19.x ✓ 5.4.198 5.4.x ✓ 5.10.122 5.10.x ✓ 5.15.47 5.15.x ✓ 5.17.15 5.17.x ✓ 5.18.4 5.18.x ✓ 5.19

References

The following references provide additional information about CVE-2022-49340 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

7 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2022-49340?

    CVE-2022-49340 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 4.19.207 onward and has been patched in 4.19.247, 5.4.198, 5.10.122 and others. CVE-2022-49340 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2022-49340?

    CVE-2022-49340 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2022-49340?

    Yes — CVE-2022-49340 has been patched. Fixed versions include 4.19.247, 5.4.198, 5.10.122 and others. If you are running Linux kernel 4.19.207 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2022-49340 actively exploited?

    No — CVE-2022-49340 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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